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Inverse dictionary lookup in Python
...as a .index method on lists the returns the first found index with the specified value or an exception if not found... any reason why such a semantic could not be applied to dictionaries?
– Brian Jack
Jun 22 '12 at 15:27
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If table exists drop table then create it, if it does not exist just create it
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Just put DROP TABLE IF EXISTS `tablename`; before your CREATE TABLE statement.
That statement drops the table if it exists but will not throw an error if it does not.
s...
Is the ternary operator faster than an “if” condition in Java [duplicate]
I am prone to " if-conditional syndrome " which means I tend to use if conditions all the time. I rarely ever use the ternary operator. For instance:
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Removing all empty elements from a hash / YAML?
...dd a compact method to Hash like this
class Hash
def compact
delete_if { |k, v| v.nil? }
end
end
or for a version that supports recursion
class Hash
def compact(opts={})
inject({}) do |new_hash, (k,v)|
if !v.nil?
new_hash[k] = opts[:recurse] && v.class == Hash...
How to exit if a command failed?
...am a noob in shell-scripting. I want to print a message and exit my script if a command fails. I've tried:
8 Answers
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How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
.... [a-z] matches any single lower case letter of the alphabet.
() Groups different matches for return purposes. See examples below.
{} Multiplier for repeated copies of pattern defined before it.
E.g. [a]{2} matches two consecutive lower case letter a: aa
E.g. [a]{1,3} matches at least one and ...
How to know if user is logged in with passport.js?
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If user is logged in, passport.js will create user object in req for every request in express.js, which you can check for existence in any middleware:
if (req.user) {
// logged in
} else {
// not logged in
}
You ca...
Copy entire contents of a directory to another using php
... @mkdir($dst);
while(false !== ( $file = readdir($dir)) ) {
if (( $file != '.' ) && ( $file != '..' )) {
if ( is_dir($src . '/' . $file) ) {
recurse_copy($src . '/' . $file,$dst . '/' . $file);
}
else {
c...
How to check if mod_rewrite is enabled in php?
I was wondering if it is possible to check if mod_rewrite is enabled on Apache AND IIS in PHP .
15 Answers
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Determine if two rectangles overlap each other?
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if (RectA.Left < RectB.Right && RectA.Right > RectB.Left &&
RectA.Top > RectB.Bottom && RectA.Bottom < RectB.Top )
or, using Cartesian coordinates
(With X1 being left coord, X...